Curable organosiloxane compositions containing an emulsified epoxide compound and elastomeric materials prepared therefrom

Abstract

This invention relates to oil-in-oil emulsions wherein the continuous phase comprises at least one carboxyalkyl terminated polydiorganosiloxane and the dispersed phase comprises at least one epoxide compound selected from diglycidyl ethers of di- and bis-phenols. The emulsions also include a curing catalyst in addition to an dispersing agent for the epoxide compound, and can be cured with heating to form elastomeric materials exhibiting properties characteristics of silicone rubber.

That which is claimed is: 
     
       1. A curable composition consisting essentially of an oil-in-oil emulsion comprising I. a continuous phase comprising from 25 to 95 percent, based on the weight of said composition, of a liquid, carboxyalkyl terminated polydiorganosiloxane containing an average of from 100 to 750 diorganosiloxane units per molecule, wherein at least 90 mole percent of said units are dimethylsiloxane, any remaining units being of the general formula R 2  SiO, and terminal units of the general formula HOOCR'--, where each R is individually selected from the group consisting of alkyl containing from 2 to 12 carbon atoms, haloalkyl containing from 1 to 3 carbon atoms and phenyl and R' represents an alkylene radical containing from 1 to 20 carbon atoms;   II. a dispersed phase comprising from 2.5 to 70 percent, based on the weight of said composition, of a liquified epoxide compound selected from the group consisting of diglycidyl ethers of di-and bis-phenols;   III. an amount sufficient to stabilize said emulsion of a solubilized dispersing agent consisting essentially of a polyorganosiloxane selected from the group consisting of (1) organosiloxane copolymers obtained by reacting (a) from 60 to 95 percent by weight of a first copolymer consisting essentially of from 45 to 72 mole percent SiO 2  units and from 28 to 55 mole percent of (CH 3 ) 3  SiO 1/2  units, and (b) from 5 to 40 percent by weight of a second copolymer consisting essentially of identical or different units of the formula R" SiO 3/2 , where R" is selected from the group consisting of alkyl containing from 1 to 4 carbon atoms and phenyl, and (2) block copolymers comprising at least one segment consisting essentially of diorganosiloxane units of the general formula R'" 2  SiO where R'" represents methyl, ethyl or vinyl and at least 95 percent of the diorganosiloxane units are polydimethylsiloxane, and at least one segment consisting essentially of one or more units of the general formula R"" YSiO or Z, where R"" is selected from the same group as R'", Y represents a monovalent polyoxyalkylene radical, Z represents a divalent polyoxyalkylene radical, Y and Z are bonded to the block copolymer by means of silicon-to-carbon or silicon-to-oxygen bonds, exhibit a molecular weight of at least 1000, and consist essentially of from 50 to 100 mole percent of polyoxyethylene units, the remaining 0 to 50 mole percent being polyoxypropylene units, and the molar ratio of diorganosiloxane units to R"" YSiO or Z units is from 400 to 800; and   IV. an amount of a liquid or solubilized catalyst sufficient to promote curing of said composition.   
     
     
       2. A composition according to claim 1 wherein R' contains from 10 to 15 carbon atoms and said carboxyalkyl terminated polydiorganosiloxane is a polydimethylsiloxane. 
     
     
       3. A composition according to claim 1 where said epoxide compound is a diglycidyl ether of a bis-phenol. 
     
     
       4. A composition according to claim 1 where the radicals represented by R"SiO 3/2  phenylsiloxy and propylsiloxy radicals. 
     
     
       5. A composition according to claim 1 where the oxyalkylene radical represented by Y contains substantially equimolar concentrations of oxyethylene and oxypropylene units. 
     
     
       6. A composition according to claim 1 where said catalyst is a secondary or tertiary organic amine. 
     
     
       7. A composition according to claim 6 where said amine is selected from the group consisting of diethanolamine, piperidine and benzyldimethylamine. 
     
     
       8. A composition according to claim 1 where said composition contains from 10 to 50 weight percent of a filler. 
     
     
       9. A composition according to claim 8 where said filler is fume silica or calcium carbonate. 
     
     
       10. A two-part composition which when blended together forms a curable oil-in oil emulsion comprising I. a continuous phase comprising from 25 to 95 percent, based on the weight of said composition, of a liquid, carboxyalkyl terminated polydiorganosiloxane containing an average of from 100 to 750 diorganosiloxane units per molecule wherein at least 90 mole percent of said units are dimethylsiloxane, any remaining diorganosiloxane units being of the general formula R 2  SiO, and terminal units of the general formula HOOCR'--, where each R is individually selected from the group consisting of alkyl containing from 2 to 12 carbon atoms, haloalkyl containing from 1 to 3 carbon atoms and phenyl and R' represents an alkylene radical containing from 1 to 20 carbon atoms;   II. a dispersed phase comprising from 2.5 to 70 percent, based on the weight of said composition, of a liquified epoxide compound selected from the group consisting of diglycidyl ethers of di-and bis-phenols;   III. an amount sufficient to stabilize said emulsion of a solubilized dispersing agent consisting essentially of a polyorganosiloxane selected from the group consisting of (1) organosiloxane copolymers obtained by reacting (a) from 60 to 95 percent by weight of a first copolymer consisting essentially of from 45 to 72 mole percent SiO 2  units and from 28 to 55 mole percent of (CH 3 ) 3  SiO 1/2  units, and (b) from 5 to 40 percent by weight of a second copolymer consisting essentially of identical or different units of the formula R" SiO3/ 2 . where R" is selected from the group consisting of alkyl containing from 1 to 4 carbon atoms and phenyl, and (2) block copolymers comprising at least one segment consisting essentially of diorganosiloxane units of the general formula R'" 2  SiO where R'" represents methyl, ethyl or vinyl and at least 95 percent of the diorganosiloxane units are polydimethylsiloxane, and at least one segment consisting essentially of one or more units of the general formula R"" YSiO or Z, where R"" is selected from the same group as R'", Y represents a monovalent polyoxyalkylene radical, Z represents a divalent polyoxyalkylene radical, Y and Z are bonded to the block copolymer by means of silicon-to-carbon or silicon-to-oxygen bonds, exhibit a molecular weight of at least 1000, and consist essentially of from 50 to 100 mole percent of polyoxyethylene units, the remaining 0 to 50 mole percent being polyoxypropylene units, and the molar ratio of diorganosiloxane units to R"" YSiO or Z units is from 400 to 800; and   IV. an amount of a liquid or solubilized catalyst sufficient to promote curing of said composition, where said liquid carboxyalkyl terminated polydiorganosiloxane and said liquified epoxide compound are in different parts of said composition.